Draft gear for railway draft rigging



Nov. 25, 1958 H. w. MULcAHY 2,861,697

DRAFT GEAR FOR RAILWAY DRAFT RGGING Filed April 27, 195e 2 sheets-sheet@ Nov. 25, 1958 f H. w. MULCAHY 2,861,697

DRAFT GEAR FOR RAILWAY DRAFT RIGGING Filed April 27', 1956 2 Sheets-Sheet 2 W q 7// /l LH E l j] l 20 f ,'H /o 1L ,11 29 l gv I /0- J 70 1 l I i7 Q. *l0 1 gni 1l /71 A f 27 27 VH 2-8 k L L L lll. 77

Zzfen/nx lin/172974! mv@ L UnitedStates Patent 'O DRAFT GEAR FOR RAILWAY DRAFT RIGGING Harry W. Mulcahy, Chicago, lll., assguor to W. H. Miner, Inc., Chicago, Ill., a corporation of Delaware Application April 27, 1956, Serial No. 581,101

Claims. (Cl. 213-49) rubber is stressed mainly in shear by operations of thel gear.

Another object of the invention is to provide an all rubber draft gear for railway draft rigging, which is of simple design and contains a small number of parts.

Further objects of the invention not specifically mentioned here will be apparent from the detailed description and claims which follow, reference being had to the accompanying drawings in which a preferred embodiment of the invention is shown by way of example and in which:

Figure 1 is a cross sectional view of the gear taken along the line 1--1 of Figure 3, looking in the direction of the arrows, with the rubber units shown in full;

Figure 2 is a View in oblique projection of a locking plate of the gear;

Figure 3 is a cross sectional View through the gear, taken along the line 3-3 of Figure l, looking in the direction of the arrows;

Figure 4 is a plan view of one of the rubber units in the relaxed state in which it is molded; and

Figure 5 is a view similar to Figure 4, showing the unit in its full travel position.

The present invention seeks to provide a rubber draft gear employing a small number of parts and in which the rubber is stressed mainly in shear by operations of the gear. To this end, in the preferred form, the gear consists of a plurality of rubber units A disposed side by side and extending longitudinally of the gear, a front end cap B, a rear end cap C, and a pair of locking plates D.

Each rubber unit A consists of a pair of metal plates and 11, disposed parallel to each other and offset one with respect to the other, and a mass of rubber 12 disposed between and bonded to the adjacent faces of plates 10 and 11. The plates 10 and 11 are rectangular in shape and adapted to be disposed with their longer edges extending longitudinally of the gear. As will be seen in Figure 4, in the relaxed state in which the unit is molded, there is an offset between the corresponding ends of plates 10 and 11 that is greater than the relative movement of the plates during operations of the gear, which offset is also greater than when the units A are assembled in the gear, as will presently appeal'. The rubber mass 12 does not engage the entire surfaces of the plates but rather terminates inwardly from one end of plate 10 and inwardly from the other end of plate 11.

The front cap B consists of a front wall 15, rearwardly extending side walls 16 and 17, a top wall 18, and a bottom wall 19, each formed integrally with the others. Side walls 16 and 17 are each provided with a generally rectangular slot 20.

The rear cap C is of similar construction consisting of a rear wall 21, forwardly extending side walls 22 and 23, a top wall and a bottom wall 24, all integrally joined together. Side walls 22 and 23 contain slots 25, which though rectangular in shape are smaller longitudinally of the gear than slots 20 in the front cap B.

Locking plates D, best seen in Figure 2, each consist of a rectangular metal plate 27,y at the front end of which is a lug 28, the forward end of which is beveled, as indicated at 29. A lug 30 of rectangular shape is disposed at the rear end of plate 27.

To assemble the gear, rear cap C is placed open end uppermost; locking plates D are placed therein with lugs 30 registered in slots 25 in which the lugs snugly t. Units A are next placed in the cap between the plates D. It will be noted that alternate units A are rotated through degrees around the longitudinal center line of the units as an axis, with the result that plate 1l) of each unit A in the stack abuts against the rear wall 21 of the cap. Plates 11, which are thus brought together in faceto-face relation, project upwardly from the upper surfaces of the rubber 12 in units A. The front cap B is then placed over the upper ends of units A and forced downwardly. The rear ends 31 of side walls 16 and 17, now positioned lowermost, engage the bevels 29 on locking plates D, forcing those plates inwardly to permit lugs 28 to pass between the walls 16 and 17. The masses of rubber 12 in units A are thus compressed. When the front wall 15 is engaged by the plates 11 of units A, further movement of the front cap B stresses the rubber 12 to build up initial resistance therein. When the cap B has been moved far enough to register lugs 28 with the slots 20, the rubber in units A expands and forces the lugs into the slots to complete assembly of the gear.

The amount of initial resistance built up in the gear during assembly may be varied, within the teachings of lthe invention, by varying the amount of offset of the plates 10 and 11 during molding, as well as by varying the composition of the rubber in mass 12. With the offset as shown in Figure 4 and movement of plates 11 to the position shown in Figure 1, desired initial resistance is built into the gear.

During operation of the gear, front cap B moves rearwardly towards rear cap C, stressing the rubber units mainly in shear. Figure 5 shows a unit A in the position it assumes at the limit of its stressing. It will be noted that plates 10 and 11 are not aligned laterally of the ligure but rather that plate 11 projects beyond plate 10 at the bottom of the figure and plate 10 projects beyond plate 11 at the top thereof. In Figure l it will be seen that the distance between the rear end 31 of the front cap B and the front end 32 of the rear cap C is less than the distances between the rear face of the front Wall 15 and the front ends of the plates 10, and between the front face of the rear wall 21 and the rear ends of the plates 11. As a result, as caps B and C are moved together, ends 31 and 32 abut together before the ends of plates 10 and 11 engage the end Walls of the caps. Thus, the abutting together of the adjacent ends of the end caps B and C limits the stressing of the units A and prevents damaging of these units by operations of the gear.

Having thus complied with the statutes and shown and described a preferred embodiment of my invention, what I consider new and desire to have protected by Letters Patent is pointed out in the appended claims.

What I claim is:

l. A draft gear for railway draft rigging, in which rubber is stressed mainly in shear during an operation vlminfml Nov. 2s, 195s ones'iof the; plates beingpoffset longitudinally with respect to the intervening plates; a pad ,of vrubber interposed between -each pair VofplatesV andbondeditheretoga pair of locking plates; disposed one V`on each side of said column; a lugprojecting outwardly from each end of each locking plate Vwith the lugs onthe front ends of the platesfbeveledattheir lfront edgesga` rearVcup-shaped cap against the inner4 face of which said alternate ones of the plates abut, there being slots inthe side walls of said cap into which therlugs on the locking platesysnugly register to x the locking plates withrespectV to said rear cap and-Withrespect to-the outer ones ofsaid rectangular plates which abut the inner ;faee of the rear cap; a front cupshaped'cap against thepinner face of which said inte-1'- vening ones of `the v-platesabut, there being elongated slots in the side Wallsjpf Asaid front `crapvinto which 'the beveled lugs onthe ,lockingplates extend. g

2.'A draft geanasspecied infrclaimv 1, inuwfnich' the rubber pads aremaintained in alignment laterally* of the gear by engagement of thelocking plates with the side 4 walls of the caps thereby to maintain the lugs on those walls in the slots in the caps.

3. A draft gear as specified in claim l, in which the ends of said plates engage the top and bottom Walls of the caps to support the plates and rubber units in the caps.

4. A draft gear as specied in claim 1, in which the rear ends of the walls of the front cap abut the front ends of the walls of the rear cap to limit the travel of the gear, thereby to protect the rubber units and the plates to which they are bonded from damage. l

5. A draft gear as specified in claim' 1, in which the Vrubber units are molded between and bonded Vto the plates with the plates offset a distance greater than the offset in the assembled gear and in which initial resistance of the column is built up by decreasing the offset of the plates during assembly of the gear.

References Cited in the le of this patent UNlTED STATES PATENTS 2,165,375 Heitner July 11, 1939 2,618,393 Withall Nov. 18, 1952 2,733,915 Dentler Feb. 7, 1956 

